Rotary harrows

ABSTRACT

A soil cultivating implement or rotary harrow has a row of soil-working members rotatably mounted on upwardly extending shafts. Driving means rotates the shafts and tools, preferably tines, are moved through the soil to work same. Fluid material from a container on a supporting structure is passed in the worked soil through injectors located adjacent the soil-working members. The injectors can be tubes arranged on a support in staggered formation across the working width of the implement, or each soil-working implement can comprise one or more injectors. The injectors extend into the ground and conduct fluid through ducts and passages from the container into the ground. A roller at the rear of the injectors smooths the worked soil.

For a better understanding of the invention, and to show how the samemay be carried into effect, reference will now be made, by way ofexample, to the accompanying drawings, in which:

FIG. 1 is a somewhat diagrammatic plan view of a soil cultivatingimplement or rotary harrow in accordance with the invention connected tothe rear of an agricultural tractor,

FIG. 2, is a side elevation, to an enlarged scale, of the implement ortractor of FIG. 1 as seen in the direction indicated by an arrow II inFIG. 1,

FIG. 3 is a part-sectional plan view, the section being taken on theline III--III in FIG. 2,

FIG. 4 is a sectional elevation illustrating an alternative constructionin which soil working members of the implement or harrow are providedwith means for introducing fluid materials into the soil,

FIG. 5 is a similar sectional elevation to FIG. 4 but illustrates theconstruction of a further alternative soil working member provided withmeans for introducing fluid materials into the soil; and

FIG. 6 is a perspective view of the impliment or harrow shown in FIG. 1.

Referring to FIGS. 1 to 3 of the accompanying drawings, the soilcultivating implement or rotary harrow which is illustrated therein willbe referred to, throughout the remaining descriptive portion of thisspecification merely as "a rotary harrow" for the sake of brevity. Therotary harrow has a supporting structure 1 which comprises a pluralityof frame beams that extend substantially horizontally transverse, andnormally substantially horizontally perpendicular, to the intendeddirection of operative travel of the harrow which is indicated by anarrow A in FIGS. 1 and 2 of the drawings. The frame beams are rigidlyinterconnected by a number of supports that all extend substantiallyparallel to the direction A. Two hollow box-shaped frame portions 2 areprovided beneath the supporting structure 1 so as to extend insubstantially longitudinal alignment with one another in a directionperpendicular to the direction A with their neighbouring ends in veryclose substantially adjoining relationship. Each frame portion 2 carriesa corresponding group of rotary soil working members. The top of eachframe portion 2 is provided, at two locations which are spaced from itsopposite ends, with corresponding upright supports 3 which, as can beseen in FIG. 2 of the drawings, are of substantially although notexactly triangular shape. The lowermost edge of each support 3 extendsthroughout the width (in the direction A) of the corresponding frameportion 2 while its leading edge with respect to the direction A issubstantially vertically disposed. The supports 3 thus taper in anupward direction and it will be noted from FIG. 1 of the drawings thatthe two supports 3 which are nearest to the substantially adjoining endsof the two frame portions 2 are closer to those substantially adjoiningends than are the other two supports 3 which are nearer to the other twoends of the two frame portions 2 that are relatively remote from oneanother. Horizontal pivots connect the ends of two arms 4 to eachsupport 3 at the front thereof with respect to the direction A and nearthe top and bottom of that support. The arms 4 extend more or lesshorizontally forwards from the corresponding supports 3 and theirleading ends are turnably connected by further substantially horizontalpivots to upright brackets 5 which are rigidly secured to one of thebeams of the supporting structure 1. As will be evident from FIG. 2 ofthe drawings, each frame portion 2 is thus connected to the framestructure 1 by a corresponding dual parallelogram linkage which allowsthat frame portion 2 to move upwardly and downwardly relative to thesupporting structure 1 during the use of the harrow independently of theother frame portion 2. Chains which are not illustrated in theaccompanying drawings are provided to limit the downward displacement ofeach frame portion 2 that can take place relative to the supportingstructure 1 during operation of the rotary harrow and during inoperativetransport of the latter.

Each frame support 2 rotatably supports, by means of corresponding upperand lower bearings, a row of twelve upwardly extending and normallysubstantially vertically disposed shafts 6, the axes of rotation of saidshafts 6 being regularly spaced apart from one another at intervalswhich preferably have magnitudes of substantially 25 centimeters. Eachshaft 6 embodies the axis of rotation of a corresponding soil workingmember 7 that is secured to a portion of that shaft 6 which projectsfrom beneath the bottom of its frame portion 2. Each soil working member7 comprises a substantially horizontal tine support 8 which is securedcentrally to the corresponding shaft 6 and two substantially verticallydisposed and substantially cylindrical tine holders 9 that areintegrally or otherwise fixedly mounted at the opposite ends of thesupport 8. The two holders 9 of each soil working member 7 receive theupper fastening portions of corresponding downwardly extending soilworking tines 10. A lower portion of each tine 10 is an active or soilworking portion which is arranged to penetrate into the soil insubstantially the manner shown in FIG. 2 of the drawings duringoperation of the harrow and which occupies a downwardly and rearwardlyinclined "trailing" disposition with respect to its overlying fasteningportion and with respect to the intended direction of rotation of thesoil working member 7 concerned (see the arrows in FIG. 3 of thedrawings). The tines 10 of each member 7 are a little further apart fromone another than are the axes of rotation embodied in immediatelyneighbouring shafts 6 so that the paths described by the lowermost freeends or tips of the active or soil working portions of those tines 10overlap one another to produce a single broad strip of worked soil inrespect of each frame portion 2 during the use of the harrow. Each shaft6 is provided, inside the corresponding hollow frame portion 2, with atoothed pinion 11 which has straight or spur teeth. The teeth of thetwelve pinions 11 that correspond to each of the two groups of soilworking members 7 are in intermeshing relationship in the manner whichcan be seen in outline in FIG. 1 of the drawings. One shaft 6 of thecentral pair of the row of twelve shafts 6 that corresponds to eachframe portion 2 has an upward extension into a corresponding gear box 12that is mounted on top of the frame portion 2 concerned. Each shaftextension is provided, inside the corresponding gear box 12, with abevel pinion whose teeth are in driven mesh with those of a furtherbevel pinion carried by a substantially horizontal shaft that extendsparallel to the length of the frame portion 2 concerned and thussubstantially perpendicular to the direction A. One splined end of eachsubstantially horizontal shaft extends into a corresponding change-speedgear 15 together with the splined end of an overlying parallel shaft.Different transmission ratios between the two shafts whose ends projectinto the corresponding change-speed gears 15 can be obtained byexchangeably and/or interchangeably mounting on those ends co-operatingpairs of straight- or spur-toothed pinions of different sizes. Eachchange-speed gear 15 comprises a releasably mounted cover which enclosesthe chosen pair of toothed pinions and maintains them free fromcontamination by dirt during the operation of the harrow.

Each of the upper substantially horizontal shafts that have ends enteredin the change-speed gears 15 has its opposite end connected by way of anoverload release clutch and a universal joint with one end of acorresponding shaft 13. The opposite and closer ends of the two shafts13 are connected by further universal joints to the ends of two outputshafts of a central gear box 14 that projects substantially horizontallyfrom opposite sides of that gear box in directions that aresubstantially perpendicular to the direction A. The central gear box 14is secured to the supporting structure 1 and has a rotary input shaftwhose splined or otherwise keyed end projects forwardly from the frontof that gear box in substantially the direction A. The rotary inputshaft is provided, inside the gear box 14, with at least one bevelpinion whose teeth are in mesh with further bevel pinions carried by thetwo output shafts of the gear box. A coupling member or trestle 16 ofgenerally triangular configuration is rigidly secured to the supportingstructure 1 at the front of that structure with respect to the directionA and enables said structure to be connected to the three-point liftingdevice or hitch at the rear of an agricultural tractor or otheroperating vehicle in the generally known manner which is illustrated inoutline in FIG. 1 of the drawings.

The relatively remote ends of the two frame portions 2 are provided withcorresponding substantially vertical shield plates 17 that both normallyextend substantially parallel to the direction A. Each shield plate 17is turnable about the axis of a corresponding upright pivot relative tothe frame portion 2 concerned to enable it to yield outwardly, againstthe action of a coil spring that is wound around the correspondingpivot, in the event of a stone of the like becoming momentarily trappedbetween the shield plate 17 and the neighbouring soil working member 7.The shield plates 17 minimise ridging at the boundaries of the broadstrip of land that is worked by the harrow and substantially preventstones and other sharp objects from being flung laterally of the path oftravel of the harrow by its rapidly moving tines 10 when the harrow isin operation. Each end of each of the two frame portions 2 comprises acorresponding substantially vertical plate alongside which acorresponding arm 18 is turnable upwardly and downwardly about asubstantially horizontal axis that is afforded by a strong pivot mountedat the top of the end plate concerned and at the front thereof withrespect to the direction A. As will be evident from FIG. 2 of thedrawings, the end plates are formed with arcuately curved slots whosecenters of curvature coincide with the positions of the correspondingpivots and the arms 18 are formed with single holes that are in registerwith the corresponding slots. Bolts are entered through the single holesand through the registering slots and can be tightened to retain thearms 18 in any chosen angular settings about the axes defined by thepivotal mountings of those arms relative to the frame portions 2. Therearmost ends of the arms 18 with respect to the direction A carrydownwardly directed brackets and two rotatable supporting members thatare in the form of open ground rollers 19 are rotatably mounted inbearings carried by the two arm brackets that correspond to each frameportion 2. Each ground roller 19 comprises a central axially mountedtubular support 20 which carries, at regular intervals along its length,a plurality of substantially vertical plates 21 (FIGS. 2 and 3), aplurality, such as eight, of tubular or rod-formation elongate elements22 being entered through peripheral holes in the plates 21 in such a waythat each element 22 is wound helically around the axis of thecorresponding tubular support 20 to some extent (see FIG. 3). It will beapparent that the angular settings of the arms 18 which are chosenrelative to the end plates of the frame portions 2 dictate the levels ofthe axes of rotation of the two rollers 19 with respect to those frameportions and thus the depths to which the tines 10 of the soil workingmembers 7 can penetrate into the ground.

The rear of each frame portion 2 with respect to the direction A carriessupporting brackets 22A to which tubular supports 23 are connected so asto extend parallel to the corresponding frame portions 2. Eachsupporting bracket 22A includes a downwardly directed portion formedwith a longitudinally extending slot 24. The slots 24 receive the shanksof pairs of fastening bolts 25 that are also entered through slots 26formed in lugs 27 carried by the corresponding tubular supports 23. Thefastening bolts 25 co-operate with the slots 24 and 26 in such a waythat the supports 23 can be raised and lowered relative to the brackets22A and be retained at chosen levels with respect to those brackets bytightening the bolts 25 after appropriate adjustment. Each support 23carries a plurality of means for introducing fluid materials into thesoil in the form of injectors 28 that are located alternately in front,and to the rear, of the support 23 concerned with respect to thedirection A, the distance between immediately neighbouring injectors 28in a direction parallel to the tubular support 23 which carries thempreferably being substantially 10 centimeters. The rows of injectors 28extend throughout the whole of the width of the strip of ground whichwill be worked by the rotary harrow during the operation thereof. Withthe arrangement which has been described, and that is illustrated in theaccompanying drawings, each support 23 will carry a front row of theinjectors 28 and a rear row thereof and it is preferred that thedistance between the two rows, measured in the direction A, should alsobe substantially 10 centimeters. It can be seen from FIG. 3 of thedrawings that the injectors 28 are located substantially midway betweenthe soil working members 7 and the ground rollers 19 with respect to thedirection A.

Each injector 28 comprises a support bar 29 of L-shaped cross-sectionwhose limbs diverge rearwardly from the leading junction between themwith respect to the direction A. The support bars 29 are inclinedrearwardly from top to bottom with respect to the direction A and thelowermost ends of the two limbs of each of them are bevelled to form alowermost tip. A tube 30 extends downwardly between the rearwardlydivergent limbs of each support bar 29 and opens at a level a shortdistance above that of the corresponding tip (see FIG. 2). The uppermostends of the tubes 30 that correspond to the injectors 28 for each groupof soil working members 7 are connected by ducts 31 to a correspondingfluid distributor 32 that is mounted beneath a corresponding fluidcontainer or tank 33. There are thus two of the tanks 33 that aremounted on brackets carried by the supporting structure 1 at locationsapproximately midway across the widths of the corresponding underlyingframe portions 2. The ducts 31 are, of course, of flexible constructionto accomodate movements of the frame portions 2 relative to thesupporting structure 1. Each tank 33 is of substantially right circularcylindrical configuration having somewhat domed opposite ends, and itslongitudinal axis is arranged substantially parallel to that of theunderlying frame portion 2 and thus substantially perpendicular to thedirection A (see FIG.1). Thus, each group of soil working members 7 isassociated with a corresponding fluid container or tank of a fluidmaterial for stimulating the growth of plants such, purely for example,as ammonia which can be introduced into the soil in a manner that isknown per se, during the use of the harrow, by way of the fluiddistributors 32, the ducts 31 and the injectors 28.

In the use of the rotary harrow that has been described with referenceto FIGS. 1 to 3 of the drawings, its coupling member of trestle 16 isconnected to the three-point lifting device or hitch at the rear of anoperating tractor or other vehicle and the rotary input shaft of thecentral gear box 14 is placed in driven connection with the powertake-off shaft of the same tractor or other vehicle by way of anintermediate telescopic transmission shaft, that is of a constructionwhich is known per se, having universal joints at its opposite ends. Thelevels of the axes of rotation of the two rollers 19 will previouslyhave been set relative to those of the corresponding frame portions 2,having regard to the nature of the soil that is to be worked and to theoperating conditions, thus dictating the depths to which the tines 10can penetrate into the soil. It will be remembered that the two groupsof soil working members 7 that corresponds to the two frame portions 2are movable upwardly and downwardly, independently of each other, withrespect to the supporting structure 1 during operation of the harrow,Also, the two change-speed gears 15 will have been pre-set to giveappropriate transmission ratios between the two shafts which each ofthem comprise so that the soil working members 7 will rotate at a fasteror slower speed wihout having to alter the input speed of rotationapplied to the central gear box 14 by the power take-off shaft of theoperating tractor or other vehicle. As the harrow moves over the groundthat is to be cultivated, neighbouring soil working members 7 rotate inthe opposite directions that are indicated by arrows in FIG. 3 of thedrawings and a plant growth stimulating material, such as fluidfertiliser which could, for example, by ammonia, is concurrentlyinserted into the soil by the injectors 28. The injection of materialtakes places in the immediate proximity of the rotary soil working tines10 and in a region between those tines and the immediately followingrollers 19 which consolidate and flatten the worked soil to some extent,simultaneously breaking up any uncrushed lumps of soil displaced by thetines 10. Thus, the fluid plant growth stimulating material is injectedinto the soil where that soil is in a well broken condition so thatmaterial can become uniformly dispersed therein. The well broken soil iscompacted to some extent substantially instantaneously after theinjection of the material so that the escape of that material from thesoil is avoided, or at least reduced, particularly when the fluidmaterial is a vaporising liquid which has a considerable tendency torevert to a gaseous condition at atmospheric pressure. Soilfertilisation by fluid materials can be carried out very effectively inthis manner with a substantially uniform distribution of the materialthrough the soil that has been treated. The fore and aft offsetarrangement of neighbouring injectors 28 (see FIG. 3 of the drawings) isa factor which conducive to the uniform distribution of a fluid materialthrough the treated soil.

FIG. 4 of the drawings illustrates an alternative embodiment in whichsoil working members 35 are themselves provided with means forintroducing fluid materials into the soil. To this end, each soilworking member 35 has a corresponding upright and normally vertical orsubstantially vertical shaft 34 that embodies its axis of rotation, thatshaft being axially hollow. Each shaft 34 is rotatably recieved insubstantially vertical ball bearings 36 and 37 carried by the upper andlower walls of the corresponding frame portion 2, respectively. A cupnut 40 or like connecting nut couples the lowermost end of the hollowshaft 43 that is illustrated in FIG. 4, and that projects from beneaththe center of the corresponding tine support 8, to the upper end of aninjector 41. The injector 41 is of circular cross-section and tapersdownwardly, a central channel 42 being formed therethrough which opensat the lowermost free end or tip of the injector 41 at a level that issomewhat higher than that of the free ends of tips of the active or soilworking portions 7A of the corresponding tines 10 but at a level whichwill normally be well below the ground surface, during operation, asillustrated in FIG. 4. In fact, the level of the lowermost free end ortip of the illustrated injector 41 is substantially threequarters of theway down between the levels of the top and bottom ends of thecorresponding tines 10. The free end or tip of the injector 41 issubstantially coincident with the axis of rotation of the soil workingmember 35.

The hollow interior of the rotary shaft 34 defines an axial channel 43that is in rectilinear connection with the upper end of the injectorchannel 42 in the region of the cup nut 40 or other connecting nut. Theuppermost end of the shaft 34 is coupled to one end of a right angledconnecting member 44 whose opposite end is linked to one of the flexibleducts 31. The end of the connecting member 44 that is remote from theduct 31 has a flange 45 which is located just inside the uppermost endof a housing 38 of the corresponding upper ball bearing 36. Theuppermost end of the axial channel 43 through the rotary shaft 34 isformed with a larger diameter recess 47 and an axially bored stud 46that is rigid with the connecting member flange 45 is entered in therecess 47. The flange 45 is maintained in place by a large cup nut 48that co-operates with a screwthread on the upper external surface of thebearing housing 38 so as to close the top of that housing. Theconnecting member 44 does not rotate with the shaft 34 during operationand it will be seen from FIG. 4 of the drawings that a fluid seal, whichis shown only diagrammatically in that Figure, is provided between theflange 45 and the ball bearing 36 around the upper end of the portion ofthe shaft 34 that is formed with the internal recess 47. In theembodiment of FIG. 4 of the drawings, the plant growth stimulating fluidmaterial is again injected into the soil in the immediate proximity ofthe active or soil working portions 7A of the tines 10 of each soilworking member 35 and, in fact at a location which substantiallycorresponds with the axis of rotation of each soil working member 35.This tends to provide an even better uniform distribution of the fluidmaterial throughout the treated soil than does the embodiment describedwith reference to FIGS. 1 to 3 of the drawings.

FIG. 5 of the drawings illustrates a further alternative construction inwhich a single soil working member 48A can be seen. The soil workingmember 48A is secured to a central upwardly extending, and normallyvertical or substantially vertical, shaft 49 which embodies its axis ofrotation and which is formed with a central axial channel 50 whoselowermost end is closed. However, the channel 50 communicates, near itslowermost closed end, with two diametrically opposed branches of achannel 51 that extends substantially axially through the two limbs of atine support 52 that is otherwise similar to one of the previouslydescribed tine supports 8. The ends of the branches of the channel 51that are remote from the center of the tine support 52 open intochambers 53 that are formed in substantially cylindrical tine holderswhich are otherwise substantially identical to the previously describedtine holders 9. The tine holders receive fastening portions at theuppermost ends of two tines 55 and those fastening portions are formedwith radial bores 54 that communicate with the chambers 53. The radialbores 54 open into axial bores 54A through the fastening portions andthose bores, in turn, communicate with channels 56 which extendlengthwise through the active or soil working portions of the tines 55to open at locations just above the free ends or tips of the latter andat the rear sides thereof with respect to the intended directions ofrotation of the corresponding soil working members 48A. In theembodiment of FIG. 5 of the drawings, the fluid material is injectedinto the soil at a greater depth, relative to the working depth, than itis in either of the two proceding embodiments. The fluid material is, infact, freed from the channels 56 at a level immediately above that ofthe lowermost free ends or tips of the trailing active or soil workingportions of the two tines 55 of each soil working member 48A. Thematerial thus escapes into the soil very close to the level of ruptureor breakage of the worked soil from the underlying undisplaced sub-soil.As, in the use of all of the embodiments, the fluid material is injectedinto the soil in the immediate proximity of the tines which break upthat soil, the well broken up structure of the soil in that regiongreatly facilitates the uniform distribution of the fluid materialthrough the soil, the helically wound substantially longitudinallyextending elements of the almost immediately following rollers 19compacting the soil so soon after the introduction of the material thatits escape from the soil is substantially completely prevented or isreduced to a very favourable extent as compared with the amount ofescape which would otherwise take place. While it is preferred to usethe tines for the displacement and consequent cultivation of the soilinto which fluid materials are to be introduced, it is noted that theemployment of the tines is not essential and that alternative soilworking tools can also be made use of. Although not mentioned it will beclear that the plant growth stimulating material also might consist offertilisers or chemicals for killing weeds and/or insects.

Although various features of the rotary harrows that have been describedand/or that are illustrated in the accompanying drawings will be setforth in the following claims as inventive feature, it is emphasisedthat the invention is not necessarily limited to those features and thatit includes within its scope each of the parts of each rotary harrowconstruction that has been described and/or that is illustrated in theaccompanying drawings both individually and in various combinations.

What we claim is:
 1. A soil cultivating implement or rotary harrowcomprising a frame and a plurality of rotatable soil working members,positioned in a row that extends transverse to the direction of travel,said members being supported on said frame to work overlapping strips ofsoil, driving means engaging said soil working members and rotating sameabout corresponding upwardly extending axes, at least one elongatedroller connected to the frame and extending transverse to the directionof travel, said roller being positioned at the rear of said row of soilworking members and having a soil engaging periphery that is formed byelongated elements which extend lengthwise with respect to the axis ofrotation of said roller, support means connected to said implement andinjectors for introducing fluid material into the worked soil beingmounted on said support means and located between the row of soilworking members and said roller, said injectors extending downwardlyfrom said support means and below the surface of the ground duringoperation.
 2. A harrow as claimed in claim 1, wherein said support meansis elongated and said injectors are mounted along the length of thesame, said injectors being located substantially midway between the rowof soil working members and said roller, with respect to the directionof travel.
 3. A harrow as claimed in claim 2, wherein said injectors arepositioned fore and aft and in offset relationship with respect to thedirection of travel.
 4. A harrow as claimed in claim 3, whereinsuccessive injectors along the length of said support means are in saidfore and aft offset relationship.
 5. A harrow as claimed in claim 4,wherein said successive injectors are supported at opposite sides ofsaid support means and the latter extends substantially parallel to saidrow of soil working members.
 6. A harrow as claimed in claim 5, whereinsaid support means is adjustably mounted on said frame and movableupwardly and downwardly, said support means having setting means thatretain said injectors in any chosen height adjustment.
 7. A harrow asclaimed in claim 6, wherein each injector comprises a substantiallystraight portion which is inclined downwardly and rearwardly from top tobottom, with respect to the direction of travel, each injector being incommunication with a fluid container via a duct on said harrow.
 8. Aharrow as claimed in claim 1, wherein there are two separate groups ofrotatable soil working members arranged in a single row and each of saidgroups is supported by a respective roller.
 9. A harrow as claimed inclaim 8, wherein there a are two fluid containers which are locatedrelative opposite sides of the center of said harrow, each of saidcontainers being mounted on a respective supporting structure thatcorresponds to one of said groups and being positioned substantiallycentrally on said structure with respect to that structure.